INCOMMING!!!! 
oops
Yep!! And here she goes
When looking at motorcycle systems and design there are a couple of things that should be taken into consideration. They are firstly the technology and materials available at the time and secondly, just what was it intended to do.
Lucas designed and built great and
good quality equipment for motorcycles given the time of manufacture. Looking back on these things I have come to believe that simplest was often the best and most reliable.
For example, My 1950 BSA Gold Flash had a six-volt system that was very reliable once it had been returned to as good as new condition. I bought another one of these bikes years later as a parts donor for mine which had come to very serious grief. I started using it, but first I re-wired it and installed a brand new proper motorcycle light unit (to replace the old yellowed car one) and fitted with the appropriate bulb. (18w x18w vertical dip vibration resistant) It also got the fully reconditioned generator of my original Gold Flash.
It put out more light than a brand new car in the next lane at the testing station. The testers could not believe it!
This and similar machines could have their entire wiring lose all its smoke (love that expression) and still you could ride it as normal. Why? Because these machines were fitted with
Magnetos! A wondrous self contained reliable device for making a spark at the plug at the right time and nothing else. They tended not to be fooled with by owners too, which probably helped quite a lot.
These days you are on the side of the road talking to your dealer if your freeking
Speedo craps out!
Lucas though could see which way the world was turning. To supply the ever increasing demand for electrical power on motor cycles the generator was going to have to get way too big. As a result they designed an alternator system for them. This was first applied to a production Triumph in 1954.
Wait What? That was years before Solid state Diodes or Transistors had even remotely come on stream. How on earth were they going to control this thing? Well they did it through switching. This wasn't the best way but it was the best they could do with the technology at the time.
It produced a complicated wiring system that while it worked, went belly up if the average motorcyclist of the day, who didn't like wires all over his machine, so much as looked at it sideways. It was this system that earned them their "Prince of Darkness" moniker. The problem was they were just a few years ahead of their time.
Most manufacturers stayed with generator systems right up into the late 1960s for this reason. One of the last to convert was guess who?
Moto Guzzi. Check out the size of the generator on a 1970 V7! It was a full size car one!
The thing is you can nearly always fix a fault with the generator system 'on the side of the road' so to speak, or at least with minimal help and technology. Good luck, though, especially in those days, finding a rectifier on your trip through Mongolia.
Once solid state rectifiers and Zenor Diodes came into play we had a simple reliable system again, though a little more complex than the old generator one, but one that was much more powerful than the by then venerable 6v 60watt generator.
Generators are still a good reliable way to supply electricity on systems where size is not an issue and are often used in such to this day.
I can honestly say that nearly all the problems I had to solve while working for Lucas were as a result of old age and neglect and/or systems being fooled with by owners who had neither the knowledge nor the skills.
There were exceptions of course, like the guy who was looking for a strange collection of electrical parts. He had been following his mates tail light one night. His mate missed a corner and sailed off a cliff into a river. The guy following, just kept doing it. Splash!
While I was there we also did a roaring trade in Lucas light units and Girling Shock absorbers for Japanese bikes. Japan appeared to be incapable of making either at that time. Their wiring systems at that time were a huge step backwards as well, but there was little that could be reasonably done about that.
I had a little side earner going re wiring bikes in those days, but I wouldn't touch a Japper. For starters I couldn't read the Japanese writing on all the little gizmos they wired in to try and make it work.
Frankly, though I was no longer working for them, I was sad when Lucas went down. The loss of resource to the public was immense as it either owned or was the distribution company for a lot of other companies. It was a one-stop shop for Girling/Lockheed, Siba(sp?) (who made mainly very high end searchlights like the ones found on fire engines up to warships.) CAV, Simms diesel, Zenith Stromberg and Solex carbs in NZ anyway, and so on.
Any questions?
Fuses.Now then, Fuses do have a life albeit a long one under ideal conditions. The thing is they have two ratings. The "This will blow it" rating, and a "continuous load" rating.
So a 15amp Lucas fuse is intended to blow if 15+amps is fed through it. How ever if loaded less than the 15amps but more than it's continuous rating (much lower. See chart below) continuously, it will shorten the life of a fuse by quite a substantial amount.
Now this, due to a misplaced key stab is the second time I written up this blurb. The first time was much more entertaining but was being done from memory alone, but this time I decided to check my facts on the way they are rated.
Guess what!
It's different in the US to the way it's done in England! Of course it is! (Cantankerous yanks! Even drive on the wrong side! They rate petrol in a unique way too)
The English (read Lucas ) way is to rate a fuse by it's "blow me now" ampage whilst the US method is to rate them by their "continuous load" rating.
Edit.
A memory stirred at this. On checking it out I found that later Lucas fuses had both ratings on them to avoid confusion. You really would not want to get these confused. If you did you could easily get a situation where the fuse held while the wiring burned!
Here is the chart.I can't vouch for the veracity of this chart and I do have some doubts about it. I note that in all cases the continuous rating is shown as 1/2 the 'fast blow rating. I have a feeling that that is a bit arbitrary and that the continuous rating should be higher than that.
British Lucas Fuse ~ American BUSS FuseFast Blow Dual Rating ~ Continuous (AGC) Alternate Opinion (SFE ?)
50 amp 25/50 amp ~ 25 amp 25 amp SFE
35 amp 17/35 amp ~ 17 amp 20 amp SFE
30 amp 15/30 amp ~ 15 amp 15 amp SFE (too short ?)
25 amp 12/25 amp ~ 12 amp 15 amp SFE (too short ?)
20 amp 10/20 amp ~ 10 amp
15 amp 7.5/15 amp ~ 8 amp
10 amp 5 /10 amp ~ 5 amp
5 amp 2.5 / 5 amp ~ 3 amp
2 amp 1 / 2 amp ~ 1 amp
I have absolutely no idea how the Italians or other Europeans do it, but I intend to find out.
At the end of the day I carry spare fuses.
If one blows for no obvious reason I will put it down to the 'Will Of Allah' (the great blower of fuses) and replace it.
If it blows again either immediately or shortly there after that indicates a fault in that circuit that will need to be found before it's used again.
Another 'Deep sigh' (we need an emoticon for that) about simple systems. The Gold Flash only had one fuse. So did the Rocket 3, though had I kept it it would have got a second one. One for the lighting and one for the ignition.
Another word about Lucas reliability. In all the 37 years I owned the Rocket 3 I only recall ever blowing a fuse once. It was a 15 amp one and occurred through uncontrolled charging current. (The Zenor had shorted out on the clutch cable)
I must admit however to going through a few Zenors (on occasion due to corrosion, but usually just on spec) and a few rectifiers.
IMHO the rectifier was the weakest point in this system which started to show up on the triples as they had a higher output alternator than other Lucas equipped bikes. The cooling of the rectifier could have been improved with better placement too. I solved the problem by fitting two of them in parallel.
venting done
